Was the cause of the father's death the evil eye, after the questioner wished she had been in her sister's place who was sitting with her father?

What happened does not seem to be an affliction of the evil eye, but rather a whisper (waswasah) that should be ignored. It is recommended to pray for mercy upon your father, and to frequently seek forgiveness and supplicate for him, and to give charity on his behalf. This is based on Prophetic hadiths that encourage showing devotion to parents after their death, such as praying for them, seeking forgiveness for them, fulfilling their pledges, maintaining kinship ties, and honoring their friends. This also includes the hadith (definition), "When the son of Adam dies, his deeds cease except for three."